Update comments now that LLVM PR3861 has been fixed. However, since conditionally removing the workaround makes the ABI dependent on LLVM version, I reconsidered that. (The same revision of LDC compiling for the same target should probably produce code that follows the same ABI, right?)

module virtcall;

extern(C) int printf(char*, ...);

class C
{
    override char[] toString()
    {
        return "overridden";
    }
}

void main()
{
    C c = new C;
    auto s = c.toString();
    printf("%.*s\n", s.length, s.ptr);
}